1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 pub use self::Variance::*;
12 pub use self::AssociatedItemContainer::*;
13 pub use self::BorrowKind::*;
14 pub use self::IntVarValue::*;
15 pub use self::fold::TypeFoldable;
17 use hir::{map as hir_map, FreevarMap, TraitMap};
19 use hir::def::{Def, CtorKind, ExportMap};
20 use hir::def_id::{CrateNum, DefId, LocalDefId, CRATE_DEF_INDEX, LOCAL_CRATE};
21 use hir::map::DefPathData;
22 use rustc_data_structures::svh::Svh;
24 use ich::StableHashingContext;
25 use infer::canonical::Canonical;
26 use middle::lang_items::{FnTraitLangItem, FnMutTraitLangItem, FnOnceTraitLangItem};
27 use middle::privacy::AccessLevels;
28 use middle::resolve_lifetime::ObjectLifetimeDefault;
30 use mir::interpret::GlobalId;
31 use mir::GeneratorLayout;
32 use session::CrateDisambiguator;
33 use traits::{self, Reveal};
35 use ty::subst::{Subst, Substs};
36 use ty::util::{IntTypeExt, Discr};
37 use ty::walk::TypeWalker;
38 use util::captures::Captures;
39 use util::nodemap::{NodeSet, DefIdMap, FxHashMap};
40 use arena::SyncDroplessArena;
41 use session::DataTypeKind;
43 use serialize::{self, Encodable, Encoder};
44 use std::cell::RefCell;
45 use std::cmp::{self, Ordering};
47 use std::hash::{Hash, Hasher};
49 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
51 use std::vec::IntoIter;
53 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
55 use syntax::ext::hygiene::Mark;
56 use syntax::symbol::{keywords, Symbol, LocalInternedString, InternedString};
57 use syntax_pos::{DUMMY_SP, Span};
60 use rustc_data_structures::stable_hasher::{StableHasher, StableHasherResult,
65 pub use self::sty::{Binder, CanonicalVar, DebruijnIndex, INNERMOST};
66 pub use self::sty::{FnSig, GenSig, PolyFnSig, PolyGenSig};
67 pub use self::sty::{InferTy, ParamTy, ProjectionTy, ExistentialPredicate};
68 pub use self::sty::{ClosureSubsts, GeneratorSubsts, UpvarSubsts, TypeAndMut};
69 pub use self::sty::{TraitRef, TyKind, PolyTraitRef};
70 pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
71 pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
72 pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
73 pub use self::sty::RegionKind;
74 pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
75 pub use self::sty::BoundRegion::*;
76 pub use self::sty::InferTy::*;
77 pub use self::sty::RegionKind::*;
78 pub use self::sty::TyKind::*;
80 pub use self::binding::BindingMode;
81 pub use self::binding::BindingMode::*;
83 pub use self::context::{TyCtxt, FreeRegionInfo, GlobalArenas, AllArenas, tls, keep_local};
84 pub use self::context::{Lift, TypeckTables};
86 pub use self::instance::{Instance, InstanceDef};
88 pub use self::trait_def::TraitDef;
90 pub use self::query::queries;
101 pub mod inhabitedness;
118 mod structural_impls;
123 /// The complete set of all analyses described in this module. This is
124 /// produced by the driver and fed to codegen and later passes.
126 /// NB: These contents are being migrated into queries using the
127 /// *on-demand* infrastructure.
129 pub struct CrateAnalysis {
130 pub access_levels: Lrc<AccessLevels>,
132 pub glob_map: Option<hir::GlobMap>,
136 pub struct Resolutions {
137 pub freevars: FreevarMap,
138 pub trait_map: TraitMap,
139 pub maybe_unused_trait_imports: NodeSet,
140 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
141 pub export_map: ExportMap,
144 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
145 pub enum AssociatedItemContainer {
146 TraitContainer(DefId),
147 ImplContainer(DefId),
150 impl AssociatedItemContainer {
151 /// Asserts that this is the def-id of an associated item declared
152 /// in a trait, and returns the trait def-id.
153 pub fn assert_trait(&self) -> DefId {
155 TraitContainer(id) => id,
156 _ => bug!("associated item has wrong container type: {:?}", self)
160 pub fn id(&self) -> DefId {
162 TraitContainer(id) => id,
163 ImplContainer(id) => id,
168 /// The "header" of an impl is everything outside the body: a Self type, a trait
169 /// ref (in the case of a trait impl), and a set of predicates (from the
170 /// bounds/where clauses).
171 #[derive(Clone, PartialEq, Eq, Hash, Debug)]
172 pub struct ImplHeader<'tcx> {
173 pub impl_def_id: DefId,
174 pub self_ty: Ty<'tcx>,
175 pub trait_ref: Option<TraitRef<'tcx>>,
176 pub predicates: Vec<Predicate<'tcx>>,
179 #[derive(Copy, Clone, Debug, PartialEq)]
180 pub struct AssociatedItem {
183 pub kind: AssociatedKind,
185 pub defaultness: hir::Defaultness,
186 pub container: AssociatedItemContainer,
188 /// Whether this is a method with an explicit self
189 /// as its first argument, allowing method calls.
190 pub method_has_self_argument: bool,
193 #[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, RustcEncodable, RustcDecodable)]
194 pub enum AssociatedKind {
201 impl AssociatedItem {
202 pub fn def(&self) -> Def {
204 AssociatedKind::Const => Def::AssociatedConst(self.def_id),
205 AssociatedKind::Method => Def::Method(self.def_id),
206 AssociatedKind::Type => Def::AssociatedTy(self.def_id),
207 AssociatedKind::Existential => Def::AssociatedExistential(self.def_id),
211 /// Tests whether the associated item admits a non-trivial implementation
213 pub fn relevant_for_never<'tcx>(&self) -> bool {
215 AssociatedKind::Existential |
216 AssociatedKind::Const |
217 AssociatedKind::Type => true,
218 // FIXME(canndrew): Be more thorough here, check if any argument is uninhabited.
219 AssociatedKind::Method => !self.method_has_self_argument,
223 pub fn signature<'a, 'tcx>(&self, tcx: &TyCtxt<'a, 'tcx, 'tcx>) -> String {
225 ty::AssociatedKind::Method => {
226 // We skip the binder here because the binder would deanonymize all
227 // late-bound regions, and we don't want method signatures to show up
228 // `as for<'r> fn(&'r MyType)`. Pretty-printing handles late-bound
229 // regions just fine, showing `fn(&MyType)`.
230 tcx.fn_sig(self.def_id).skip_binder().to_string()
232 ty::AssociatedKind::Type => format!("type {};", self.ident),
233 ty::AssociatedKind::Existential => format!("existential type {};", self.ident),
234 ty::AssociatedKind::Const => {
235 format!("const {}: {:?};", self.ident, tcx.type_of(self.def_id))
241 #[derive(Clone, Debug, PartialEq, Eq, Copy, RustcEncodable, RustcDecodable)]
242 pub enum Visibility {
243 /// Visible everywhere (including in other crates).
245 /// Visible only in the given crate-local module.
247 /// Not visible anywhere in the local crate. This is the visibility of private external items.
251 pub trait DefIdTree: Copy {
252 fn parent(self, id: DefId) -> Option<DefId>;
254 fn is_descendant_of(self, mut descendant: DefId, ancestor: DefId) -> bool {
255 if descendant.krate != ancestor.krate {
259 while descendant != ancestor {
260 match self.parent(descendant) {
261 Some(parent) => descendant = parent,
262 None => return false,
269 impl<'a, 'gcx, 'tcx> DefIdTree for TyCtxt<'a, 'gcx, 'tcx> {
270 fn parent(self, id: DefId) -> Option<DefId> {
271 self.def_key(id).parent.map(|index| DefId { index: index, ..id })
276 pub fn from_hir(visibility: &hir::Visibility, id: NodeId, tcx: TyCtxt) -> Self {
277 match visibility.node {
278 hir::VisibilityKind::Public => Visibility::Public,
279 hir::VisibilityKind::Crate(_) => Visibility::Restricted(DefId::local(CRATE_DEF_INDEX)),
280 hir::VisibilityKind::Restricted { ref path, .. } => match path.def {
281 // If there is no resolution, `resolve` will have already reported an error, so
282 // assume that the visibility is public to avoid reporting more privacy errors.
283 Def::Err => Visibility::Public,
284 def => Visibility::Restricted(def.def_id()),
286 hir::VisibilityKind::Inherited => {
287 Visibility::Restricted(tcx.hir.get_module_parent(id))
292 /// Returns true if an item with this visibility is accessible from the given block.
293 pub fn is_accessible_from<T: DefIdTree>(self, module: DefId, tree: T) -> bool {
294 let restriction = match self {
295 // Public items are visible everywhere.
296 Visibility::Public => return true,
297 // Private items from other crates are visible nowhere.
298 Visibility::Invisible => return false,
299 // Restricted items are visible in an arbitrary local module.
300 Visibility::Restricted(other) if other.krate != module.krate => return false,
301 Visibility::Restricted(module) => module,
304 tree.is_descendant_of(module, restriction)
307 /// Returns true if this visibility is at least as accessible as the given visibility
308 pub fn is_at_least<T: DefIdTree>(self, vis: Visibility, tree: T) -> bool {
309 let vis_restriction = match vis {
310 Visibility::Public => return self == Visibility::Public,
311 Visibility::Invisible => return true,
312 Visibility::Restricted(module) => module,
315 self.is_accessible_from(vis_restriction, tree)
318 // Returns true if this item is visible anywhere in the local crate.
319 pub fn is_visible_locally(self) -> bool {
321 Visibility::Public => true,
322 Visibility::Restricted(def_id) => def_id.is_local(),
323 Visibility::Invisible => false,
328 #[derive(Clone, PartialEq, RustcDecodable, RustcEncodable, Copy)]
330 Covariant, // T<A> <: T<B> iff A <: B -- e.g., function return type
331 Invariant, // T<A> <: T<B> iff B == A -- e.g., type of mutable cell
332 Contravariant, // T<A> <: T<B> iff B <: A -- e.g., function param type
333 Bivariant, // T<A> <: T<B> -- e.g., unused type parameter
336 /// The crate variances map is computed during typeck and contains the
337 /// variance of every item in the local crate. You should not use it
338 /// directly, because to do so will make your pass dependent on the
339 /// HIR of every item in the local crate. Instead, use
340 /// `tcx.variances_of()` to get the variance for a *particular*
342 pub struct CrateVariancesMap {
343 /// For each item with generics, maps to a vector of the variance
344 /// of its generics. If an item has no generics, it will have no
346 pub variances: FxHashMap<DefId, Lrc<Vec<ty::Variance>>>,
348 /// An empty vector, useful for cloning.
349 pub empty_variance: Lrc<Vec<ty::Variance>>,
353 /// `a.xform(b)` combines the variance of a context with the
354 /// variance of a type with the following meaning. If we are in a
355 /// context with variance `a`, and we encounter a type argument in
356 /// a position with variance `b`, then `a.xform(b)` is the new
357 /// variance with which the argument appears.
363 /// Here, the "ambient" variance starts as covariant. `*mut T` is
364 /// invariant with respect to `T`, so the variance in which the
365 /// `Vec<i32>` appears is `Covariant.xform(Invariant)`, which
366 /// yields `Invariant`. Now, the type `Vec<T>` is covariant with
367 /// respect to its type argument `T`, and hence the variance of
368 /// the `i32` here is `Invariant.xform(Covariant)`, which results
369 /// (again) in `Invariant`.
373 /// fn(*const Vec<i32>, *mut Vec<i32)
375 /// The ambient variance is covariant. A `fn` type is
376 /// contravariant with respect to its parameters, so the variance
377 /// within which both pointer types appear is
378 /// `Covariant.xform(Contravariant)`, or `Contravariant`. `*const
379 /// T` is covariant with respect to `T`, so the variance within
380 /// which the first `Vec<i32>` appears is
381 /// `Contravariant.xform(Covariant)` or `Contravariant`. The same
382 /// is true for its `i32` argument. In the `*mut T` case, the
383 /// variance of `Vec<i32>` is `Contravariant.xform(Invariant)`,
384 /// and hence the outermost type is `Invariant` with respect to
385 /// `Vec<i32>` (and its `i32` argument).
387 /// Source: Figure 1 of "Taming the Wildcards:
388 /// Combining Definition- and Use-Site Variance" published in PLDI'11.
389 pub fn xform(self, v: ty::Variance) -> ty::Variance {
391 // Figure 1, column 1.
392 (ty::Covariant, ty::Covariant) => ty::Covariant,
393 (ty::Covariant, ty::Contravariant) => ty::Contravariant,
394 (ty::Covariant, ty::Invariant) => ty::Invariant,
395 (ty::Covariant, ty::Bivariant) => ty::Bivariant,
397 // Figure 1, column 2.
398 (ty::Contravariant, ty::Covariant) => ty::Contravariant,
399 (ty::Contravariant, ty::Contravariant) => ty::Covariant,
400 (ty::Contravariant, ty::Invariant) => ty::Invariant,
401 (ty::Contravariant, ty::Bivariant) => ty::Bivariant,
403 // Figure 1, column 3.
404 (ty::Invariant, _) => ty::Invariant,
406 // Figure 1, column 4.
407 (ty::Bivariant, _) => ty::Bivariant,
412 // Contains information needed to resolve types and (in the future) look up
413 // the types of AST nodes.
414 #[derive(Copy, Clone, PartialEq, Eq, Hash)]
415 pub struct CReaderCacheKey {
420 // Flags that we track on types. These flags are propagated upwards
421 // through the type during type construction, so that we can quickly
422 // check whether the type has various kinds of types in it without
423 // recursing over the type itself.
425 pub struct TypeFlags: u32 {
426 const HAS_PARAMS = 1 << 0;
427 const HAS_SELF = 1 << 1;
428 const HAS_TY_INFER = 1 << 2;
429 const HAS_RE_INFER = 1 << 3;
430 const HAS_RE_SKOL = 1 << 4;
432 /// Does this have any `ReEarlyBound` regions? Used to
433 /// determine whether substitition is required, since those
434 /// represent regions that are bound in a `ty::Generics` and
435 /// hence may be substituted.
436 const HAS_RE_EARLY_BOUND = 1 << 5;
438 /// Does this have any region that "appears free" in the type?
439 /// Basically anything but `ReLateBound` and `ReErased`.
440 const HAS_FREE_REGIONS = 1 << 6;
442 /// Is an error type reachable?
443 const HAS_TY_ERR = 1 << 7;
444 const HAS_PROJECTION = 1 << 8;
446 // FIXME: Rename this to the actual property since it's used for generators too
447 const HAS_TY_CLOSURE = 1 << 9;
449 // true if there are "names" of types and regions and so forth
450 // that are local to a particular fn
451 const HAS_FREE_LOCAL_NAMES = 1 << 10;
453 // Present if the type belongs in a local type context.
454 // Only set for Infer other than Fresh.
455 const KEEP_IN_LOCAL_TCX = 1 << 11;
457 // Is there a projection that does not involve a bound region?
458 // Currently we can't normalize projections w/ bound regions.
459 const HAS_NORMALIZABLE_PROJECTION = 1 << 12;
461 // Set if this includes a "canonical" type or region var --
462 // ought to be true only for the results of canonicalization.
463 const HAS_CANONICAL_VARS = 1 << 13;
465 /// Does this have any `ReLateBound` regions? Used to check
466 /// if a global bound is safe to evaluate.
467 const HAS_RE_LATE_BOUND = 1 << 14;
469 const NEEDS_SUBST = TypeFlags::HAS_PARAMS.bits |
470 TypeFlags::HAS_SELF.bits |
471 TypeFlags::HAS_RE_EARLY_BOUND.bits;
473 // Flags representing the nominal content of a type,
474 // computed by FlagsComputation. If you add a new nominal
475 // flag, it should be added here too.
476 const NOMINAL_FLAGS = TypeFlags::HAS_PARAMS.bits |
477 TypeFlags::HAS_SELF.bits |
478 TypeFlags::HAS_TY_INFER.bits |
479 TypeFlags::HAS_RE_INFER.bits |
480 TypeFlags::HAS_RE_SKOL.bits |
481 TypeFlags::HAS_RE_EARLY_BOUND.bits |
482 TypeFlags::HAS_FREE_REGIONS.bits |
483 TypeFlags::HAS_TY_ERR.bits |
484 TypeFlags::HAS_PROJECTION.bits |
485 TypeFlags::HAS_TY_CLOSURE.bits |
486 TypeFlags::HAS_FREE_LOCAL_NAMES.bits |
487 TypeFlags::KEEP_IN_LOCAL_TCX.bits |
488 TypeFlags::HAS_CANONICAL_VARS.bits |
489 TypeFlags::HAS_RE_LATE_BOUND.bits;
493 pub struct TyS<'tcx> {
494 pub sty: TyKind<'tcx>,
495 pub flags: TypeFlags,
497 /// This is a kind of confusing thing: it stores the smallest
500 /// (a) the binder itself captures nothing but
501 /// (b) all the late-bound things within the type are captured
502 /// by some sub-binder.
504 /// So, for a type without any late-bound things, like `u32`, this
505 /// will be INNERMOST, because that is the innermost binder that
506 /// captures nothing. But for a type `&'D u32`, where `'D` is a
507 /// late-bound region with debruijn index D, this would be D+1 --
508 /// the binder itself does not capture D, but D is captured by an
511 /// We call this concept an "exclusive" binder D (because all
512 /// debruijn indices within the type are contained within `0..D`
514 outer_exclusive_binder: ty::DebruijnIndex,
517 impl<'tcx> Ord for TyS<'tcx> {
518 fn cmp(&self, other: &TyS<'tcx>) -> Ordering {
519 self.sty.cmp(&other.sty)
523 impl<'tcx> PartialOrd for TyS<'tcx> {
524 fn partial_cmp(&self, other: &TyS<'tcx>) -> Option<Ordering> {
525 Some(self.sty.cmp(&other.sty))
529 impl<'tcx> PartialEq for TyS<'tcx> {
531 fn eq(&self, other: &TyS<'tcx>) -> bool {
535 impl<'tcx> Eq for TyS<'tcx> {}
537 impl<'tcx> Hash for TyS<'tcx> {
538 fn hash<H: Hasher>(&self, s: &mut H) {
539 (self as *const TyS).hash(s)
543 impl<'tcx> TyS<'tcx> {
544 pub fn is_primitive_ty(&self) -> bool {
551 TyKind::Infer(InferTy::IntVar(_)) |
552 TyKind::Infer(InferTy::FloatVar(_)) |
553 TyKind::Infer(InferTy::FreshIntTy(_)) |
554 TyKind::Infer(InferTy::FreshFloatTy(_)) => true,
555 TyKind::Ref(_, x, _) => x.is_primitive_ty(),
560 pub fn is_suggestable(&self) -> bool {
565 TyKind::Dynamic(..) |
566 TyKind::Closure(..) |
568 TyKind::Projection(..) => false,
574 impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for ty::TyS<'gcx> {
575 fn hash_stable<W: StableHasherResult>(&self,
576 hcx: &mut StableHashingContext<'a>,
577 hasher: &mut StableHasher<W>) {
581 // The other fields just provide fast access to information that is
582 // also contained in `sty`, so no need to hash them.
585 outer_exclusive_binder: _,
588 sty.hash_stable(hcx, hasher);
592 pub type Ty<'tcx> = &'tcx TyS<'tcx>;
594 impl<'tcx> serialize::UseSpecializedEncodable for Ty<'tcx> {}
595 impl<'tcx> serialize::UseSpecializedDecodable for Ty<'tcx> {}
597 pub type CanonicalTy<'gcx> = Canonical<'gcx, Ty<'gcx>>;
600 /// A dummy type used to force List to by unsized without requiring fat pointers
601 type OpaqueListContents;
604 /// A wrapper for slices with the additional invariant
605 /// that the slice is interned and no other slice with
606 /// the same contents can exist in the same context.
607 /// This means we can use pointer for both
608 /// equality comparisons and hashing.
609 /// Note: `Slice` was already taken by the `Ty`.
614 opaque: OpaqueListContents,
617 unsafe impl<T: Sync> Sync for List<T> {}
619 impl<T: Copy> List<T> {
621 fn from_arena<'tcx>(arena: &'tcx SyncDroplessArena, slice: &[T]) -> &'tcx List<T> {
622 assert!(!mem::needs_drop::<T>());
623 assert!(mem::size_of::<T>() != 0);
624 assert!(slice.len() != 0);
626 // Align up the size of the len (usize) field
627 let align = mem::align_of::<T>();
628 let align_mask = align - 1;
629 let offset = mem::size_of::<usize>();
630 let offset = (offset + align_mask) & !align_mask;
632 let size = offset + slice.len() * mem::size_of::<T>();
634 let mem = arena.alloc_raw(
636 cmp::max(mem::align_of::<T>(), mem::align_of::<usize>()));
638 let result = &mut *(mem.as_mut_ptr() as *mut List<T>);
640 result.len = slice.len();
642 // Write the elements
643 let arena_slice = slice::from_raw_parts_mut(result.data.as_mut_ptr(), result.len);
644 arena_slice.copy_from_slice(slice);
651 impl<T: fmt::Debug> fmt::Debug for List<T> {
652 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
657 impl<T: Encodable> Encodable for List<T> {
659 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
664 impl<T> Ord for List<T> where T: Ord {
665 fn cmp(&self, other: &List<T>) -> Ordering {
666 if self == other { Ordering::Equal } else {
667 <[T] as Ord>::cmp(&**self, &**other)
672 impl<T> PartialOrd for List<T> where T: PartialOrd {
673 fn partial_cmp(&self, other: &List<T>) -> Option<Ordering> {
674 if self == other { Some(Ordering::Equal) } else {
675 <[T] as PartialOrd>::partial_cmp(&**self, &**other)
680 impl<T: PartialEq> PartialEq for List<T> {
682 fn eq(&self, other: &List<T>) -> bool {
686 impl<T: Eq> Eq for List<T> {}
688 impl<T> Hash for List<T> {
690 fn hash<H: Hasher>(&self, s: &mut H) {
691 (self as *const List<T>).hash(s)
695 impl<T> Deref for List<T> {
698 fn deref(&self) -> &[T] {
700 slice::from_raw_parts(self.data.as_ptr(), self.len)
705 impl<'a, T> IntoIterator for &'a List<T> {
707 type IntoIter = <&'a [T] as IntoIterator>::IntoIter;
709 fn into_iter(self) -> Self::IntoIter {
714 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx List<Ty<'tcx>> {}
718 pub fn empty<'a>() -> &'a List<T> {
719 #[repr(align(64), C)]
720 struct EmptySlice([u8; 64]);
721 static EMPTY_SLICE: EmptySlice = EmptySlice([0; 64]);
722 assert!(mem::align_of::<T>() <= 64);
724 &*(&EMPTY_SLICE as *const _ as *const List<T>)
729 /// Upvars do not get their own node-id. Instead, we use the pair of
730 /// the original var id (that is, the root variable that is referenced
731 /// by the upvar) and the id of the closure expression.
732 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
734 pub var_id: hir::HirId,
735 pub closure_expr_id: LocalDefId,
738 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable, Copy)]
739 pub enum BorrowKind {
740 /// Data must be immutable and is aliasable.
743 /// Data must be immutable but not aliasable. This kind of borrow
744 /// cannot currently be expressed by the user and is used only in
745 /// implicit closure bindings. It is needed when the closure
746 /// is borrowing or mutating a mutable referent, e.g.:
748 /// let x: &mut isize = ...;
749 /// let y = || *x += 5;
751 /// If we were to try to translate this closure into a more explicit
752 /// form, we'd encounter an error with the code as written:
754 /// struct Env { x: & &mut isize }
755 /// let x: &mut isize = ...;
756 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
757 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
759 /// This is then illegal because you cannot mutate a `&mut` found
760 /// in an aliasable location. To solve, you'd have to translate with
761 /// an `&mut` borrow:
763 /// struct Env { x: & &mut isize }
764 /// let x: &mut isize = ...;
765 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
766 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
768 /// Now the assignment to `**env.x` is legal, but creating a
769 /// mutable pointer to `x` is not because `x` is not mutable. We
770 /// could fix this by declaring `x` as `let mut x`. This is ok in
771 /// user code, if awkward, but extra weird for closures, since the
772 /// borrow is hidden.
774 /// So we introduce a "unique imm" borrow -- the referent is
775 /// immutable, but not aliasable. This solves the problem. For
776 /// simplicity, we don't give users the way to express this
777 /// borrow, it's just used when translating closures.
780 /// Data is mutable and not aliasable.
784 /// Information describing the capture of an upvar. This is computed
785 /// during `typeck`, specifically by `regionck`.
786 #[derive(PartialEq, Clone, Debug, Copy, RustcEncodable, RustcDecodable)]
787 pub enum UpvarCapture<'tcx> {
788 /// Upvar is captured by value. This is always true when the
789 /// closure is labeled `move`, but can also be true in other cases
790 /// depending on inference.
793 /// Upvar is captured by reference.
794 ByRef(UpvarBorrow<'tcx>),
797 #[derive(PartialEq, Clone, Copy, RustcEncodable, RustcDecodable)]
798 pub struct UpvarBorrow<'tcx> {
799 /// The kind of borrow: by-ref upvars have access to shared
800 /// immutable borrows, which are not part of the normal language
802 pub kind: BorrowKind,
804 /// Region of the resulting reference.
805 pub region: ty::Region<'tcx>,
808 pub type UpvarCaptureMap<'tcx> = FxHashMap<UpvarId, UpvarCapture<'tcx>>;
810 #[derive(Copy, Clone)]
811 pub struct ClosureUpvar<'tcx> {
817 #[derive(Clone, Copy, PartialEq, Eq)]
818 pub enum IntVarValue {
820 UintType(ast::UintTy),
823 #[derive(Clone, Copy, PartialEq, Eq)]
824 pub struct FloatVarValue(pub ast::FloatTy);
826 impl ty::EarlyBoundRegion {
827 pub fn to_bound_region(&self) -> ty::BoundRegion {
828 ty::BoundRegion::BrNamed(self.def_id, self.name)
831 /// Does this early bound region have a name? Early bound regions normally
832 /// always have names except when using anonymous lifetimes (`'_`).
833 pub fn has_name(&self) -> bool {
834 self.name != keywords::UnderscoreLifetime.name().as_interned_str()
838 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
839 pub enum GenericParamDefKind {
843 object_lifetime_default: ObjectLifetimeDefault,
844 synthetic: Option<hir::SyntheticTyParamKind>,
848 #[derive(Clone, RustcEncodable, RustcDecodable)]
849 pub struct GenericParamDef {
850 pub name: InternedString,
854 /// `pure_wrt_drop`, set by the (unsafe) `#[may_dangle]` attribute
855 /// on generic parameter `'a`/`T`, asserts data behind the parameter
856 /// `'a`/`T` won't be accessed during the parent type's `Drop` impl.
857 pub pure_wrt_drop: bool,
859 pub kind: GenericParamDefKind,
862 impl GenericParamDef {
863 pub fn to_early_bound_region_data(&self) -> ty::EarlyBoundRegion {
865 GenericParamDefKind::Lifetime => {
866 ty::EarlyBoundRegion {
872 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
876 pub fn to_bound_region(&self) -> ty::BoundRegion {
878 GenericParamDefKind::Lifetime => {
879 self.to_early_bound_region_data().to_bound_region()
881 _ => bug!("cannot convert a non-lifetime parameter def to an early bound region")
887 pub struct GenericParamCount {
888 pub lifetimes: usize,
892 /// Information about the formal type/lifetime parameters associated
893 /// with an item or method. Analogous to hir::Generics.
895 /// The ordering of parameters is the same as in Subst (excluding child generics):
896 /// Self (optionally), Lifetime params..., Type params...
897 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
898 pub struct Generics {
899 pub parent: Option<DefId>,
900 pub parent_count: usize,
901 pub params: Vec<GenericParamDef>,
903 /// Reverse map to the `index` field of each `GenericParamDef`
904 pub param_def_id_to_index: FxHashMap<DefId, u32>,
907 pub has_late_bound_regions: Option<Span>,
910 impl<'a, 'gcx, 'tcx> Generics {
911 pub fn count(&self) -> usize {
912 self.parent_count + self.params.len()
915 pub fn own_counts(&self) -> GenericParamCount {
916 // We could cache this as a property of `GenericParamCount`, but
917 // the aim is to refactor this away entirely eventually and the
918 // presence of this method will be a constant reminder.
919 let mut own_counts: GenericParamCount = Default::default();
921 for param in &self.params {
923 GenericParamDefKind::Lifetime => own_counts.lifetimes += 1,
924 GenericParamDefKind::Type { .. } => own_counts.types += 1,
931 pub fn requires_monomorphization(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
932 for param in &self.params {
934 GenericParamDefKind::Type { .. } => return true,
935 GenericParamDefKind::Lifetime => {}
938 if let Some(parent_def_id) = self.parent {
939 let parent = tcx.generics_of(parent_def_id);
940 parent.requires_monomorphization(tcx)
946 pub fn region_param(&'tcx self,
947 param: &EarlyBoundRegion,
948 tcx: TyCtxt<'a, 'gcx, 'tcx>)
949 -> &'tcx GenericParamDef
951 if let Some(index) = param.index.checked_sub(self.parent_count as u32) {
952 let param = &self.params[index as usize];
954 ty::GenericParamDefKind::Lifetime => param,
955 _ => bug!("expected lifetime parameter, but found another generic parameter")
958 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
959 .region_param(param, tcx)
963 /// Returns the `GenericParamDef` associated with this `ParamTy`.
964 pub fn type_param(&'tcx self,
966 tcx: TyCtxt<'a, 'gcx, 'tcx>)
967 -> &'tcx GenericParamDef {
968 if let Some(index) = param.idx.checked_sub(self.parent_count as u32) {
969 let param = &self.params[index as usize];
971 ty::GenericParamDefKind::Type {..} => param,
972 _ => bug!("expected type parameter, but found another generic parameter")
975 tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
976 .type_param(param, tcx)
981 /// Bounds on generics.
982 #[derive(Clone, Default)]
983 pub struct GenericPredicates<'tcx> {
984 pub parent: Option<DefId>,
985 pub predicates: Vec<Predicate<'tcx>>,
988 impl<'tcx> serialize::UseSpecializedEncodable for GenericPredicates<'tcx> {}
989 impl<'tcx> serialize::UseSpecializedDecodable for GenericPredicates<'tcx> {}
991 impl<'a, 'gcx, 'tcx> GenericPredicates<'tcx> {
992 pub fn instantiate(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
993 -> InstantiatedPredicates<'tcx> {
994 let mut instantiated = InstantiatedPredicates::empty();
995 self.instantiate_into(tcx, &mut instantiated, substs);
998 pub fn instantiate_own(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, substs: &Substs<'tcx>)
999 -> InstantiatedPredicates<'tcx> {
1000 InstantiatedPredicates {
1001 predicates: self.predicates.subst(tcx, substs)
1005 fn instantiate_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1006 instantiated: &mut InstantiatedPredicates<'tcx>,
1007 substs: &Substs<'tcx>) {
1008 if let Some(def_id) = self.parent {
1009 tcx.predicates_of(def_id).instantiate_into(tcx, instantiated, substs);
1011 instantiated.predicates.extend(self.predicates.iter().map(|p| p.subst(tcx, substs)))
1014 pub fn instantiate_identity(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>)
1015 -> InstantiatedPredicates<'tcx> {
1016 let mut instantiated = InstantiatedPredicates::empty();
1017 self.instantiate_identity_into(tcx, &mut instantiated);
1021 fn instantiate_identity_into(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1022 instantiated: &mut InstantiatedPredicates<'tcx>) {
1023 if let Some(def_id) = self.parent {
1024 tcx.predicates_of(def_id).instantiate_identity_into(tcx, instantiated);
1026 instantiated.predicates.extend(&self.predicates)
1029 pub fn instantiate_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1030 poly_trait_ref: &ty::PolyTraitRef<'tcx>)
1031 -> InstantiatedPredicates<'tcx>
1033 assert_eq!(self.parent, None);
1034 InstantiatedPredicates {
1035 predicates: self.predicates.iter().map(|pred| {
1036 pred.subst_supertrait(tcx, poly_trait_ref)
1042 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1043 pub enum Predicate<'tcx> {
1044 /// Corresponds to `where Foo : Bar<A,B,C>`. `Foo` here would be
1045 /// the `Self` type of the trait reference and `A`, `B`, and `C`
1046 /// would be the type parameters.
1047 Trait(PolyTraitPredicate<'tcx>),
1050 RegionOutlives(PolyRegionOutlivesPredicate<'tcx>),
1053 TypeOutlives(PolyTypeOutlivesPredicate<'tcx>),
1055 /// where <T as TraitRef>::Name == X, approximately.
1056 /// See `ProjectionPredicate` struct for details.
1057 Projection(PolyProjectionPredicate<'tcx>),
1060 WellFormed(Ty<'tcx>),
1062 /// trait must be object-safe
1065 /// No direct syntax. May be thought of as `where T : FnFoo<...>`
1066 /// for some substitutions `...` and T being a closure type.
1067 /// Satisfied (or refuted) once we know the closure's kind.
1068 ClosureKind(DefId, ClosureSubsts<'tcx>, ClosureKind),
1071 Subtype(PolySubtypePredicate<'tcx>),
1073 /// Constant initializer must evaluate successfully.
1074 ConstEvaluatable(DefId, &'tcx Substs<'tcx>),
1077 /// The crate outlives map is computed during typeck and contains the
1078 /// outlives of every item in the local crate. You should not use it
1079 /// directly, because to do so will make your pass dependent on the
1080 /// HIR of every item in the local crate. Instead, use
1081 /// `tcx.inferred_outlives_of()` to get the outlives for a *particular*
1083 pub struct CratePredicatesMap<'tcx> {
1084 /// For each struct with outlive bounds, maps to a vector of the
1085 /// predicate of its outlive bounds. If an item has no outlives
1086 /// bounds, it will have no entry.
1087 pub predicates: FxHashMap<DefId, Lrc<Vec<ty::Predicate<'tcx>>>>,
1089 /// An empty vector, useful for cloning.
1090 pub empty_predicate: Lrc<Vec<ty::Predicate<'tcx>>>,
1093 impl<'tcx> AsRef<Predicate<'tcx>> for Predicate<'tcx> {
1094 fn as_ref(&self) -> &Predicate<'tcx> {
1099 impl<'a, 'gcx, 'tcx> Predicate<'tcx> {
1100 /// Performs a substitution suitable for going from a
1101 /// poly-trait-ref to supertraits that must hold if that
1102 /// poly-trait-ref holds. This is slightly different from a normal
1103 /// substitution in terms of what happens with bound regions. See
1104 /// lengthy comment below for details.
1105 pub fn subst_supertrait(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
1106 trait_ref: &ty::PolyTraitRef<'tcx>)
1107 -> ty::Predicate<'tcx>
1109 // The interaction between HRTB and supertraits is not entirely
1110 // obvious. Let me walk you (and myself) through an example.
1112 // Let's start with an easy case. Consider two traits:
1114 // trait Foo<'a> : Bar<'a,'a> { }
1115 // trait Bar<'b,'c> { }
1117 // Now, if we have a trait reference `for<'x> T : Foo<'x>`, then
1118 // we can deduce that `for<'x> T : Bar<'x,'x>`. Basically, if we
1119 // knew that `Foo<'x>` (for any 'x) then we also know that
1120 // `Bar<'x,'x>` (for any 'x). This more-or-less falls out from
1121 // normal substitution.
1123 // In terms of why this is sound, the idea is that whenever there
1124 // is an impl of `T:Foo<'a>`, it must show that `T:Bar<'a,'a>`
1125 // holds. So if there is an impl of `T:Foo<'a>` that applies to
1126 // all `'a`, then we must know that `T:Bar<'a,'a>` holds for all
1129 // Another example to be careful of is this:
1131 // trait Foo1<'a> : for<'b> Bar1<'a,'b> { }
1132 // trait Bar1<'b,'c> { }
1134 // Here, if we have `for<'x> T : Foo1<'x>`, then what do we know?
1135 // The answer is that we know `for<'x,'b> T : Bar1<'x,'b>`. The
1136 // reason is similar to the previous example: any impl of
1137 // `T:Foo1<'x>` must show that `for<'b> T : Bar1<'x, 'b>`. So
1138 // basically we would want to collapse the bound lifetimes from
1139 // the input (`trait_ref`) and the supertraits.
1141 // To achieve this in practice is fairly straightforward. Let's
1142 // consider the more complicated scenario:
1144 // - We start out with `for<'x> T : Foo1<'x>`. In this case, `'x`
1145 // has a De Bruijn index of 1. We want to produce `for<'x,'b> T : Bar1<'x,'b>`,
1146 // where both `'x` and `'b` would have a DB index of 1.
1147 // The substitution from the input trait-ref is therefore going to be
1148 // `'a => 'x` (where `'x` has a DB index of 1).
1149 // - The super-trait-ref is `for<'b> Bar1<'a,'b>`, where `'a` is an
1150 // early-bound parameter and `'b' is a late-bound parameter with a
1152 // - If we replace `'a` with `'x` from the input, it too will have
1153 // a DB index of 1, and thus we'll have `for<'x,'b> Bar1<'x,'b>`
1154 // just as we wanted.
1156 // There is only one catch. If we just apply the substitution `'a
1157 // => 'x` to `for<'b> Bar1<'a,'b>`, the substitution code will
1158 // adjust the DB index because we substituting into a binder (it
1159 // tries to be so smart...) resulting in `for<'x> for<'b>
1160 // Bar1<'x,'b>` (we have no syntax for this, so use your
1161 // imagination). Basically the 'x will have DB index of 2 and 'b
1162 // will have DB index of 1. Not quite what we want. So we apply
1163 // the substitution to the *contents* of the trait reference,
1164 // rather than the trait reference itself (put another way, the
1165 // substitution code expects equal binding levels in the values
1166 // from the substitution and the value being substituted into, and
1167 // this trick achieves that).
1169 let substs = &trait_ref.skip_binder().substs;
1171 Predicate::Trait(ref binder) =>
1172 Predicate::Trait(binder.map_bound(|data| data.subst(tcx, substs))),
1173 Predicate::Subtype(ref binder) =>
1174 Predicate::Subtype(binder.map_bound(|data| data.subst(tcx, substs))),
1175 Predicate::RegionOutlives(ref binder) =>
1176 Predicate::RegionOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1177 Predicate::TypeOutlives(ref binder) =>
1178 Predicate::TypeOutlives(binder.map_bound(|data| data.subst(tcx, substs))),
1179 Predicate::Projection(ref binder) =>
1180 Predicate::Projection(binder.map_bound(|data| data.subst(tcx, substs))),
1181 Predicate::WellFormed(data) =>
1182 Predicate::WellFormed(data.subst(tcx, substs)),
1183 Predicate::ObjectSafe(trait_def_id) =>
1184 Predicate::ObjectSafe(trait_def_id),
1185 Predicate::ClosureKind(closure_def_id, closure_substs, kind) =>
1186 Predicate::ClosureKind(closure_def_id, closure_substs.subst(tcx, substs), kind),
1187 Predicate::ConstEvaluatable(def_id, const_substs) =>
1188 Predicate::ConstEvaluatable(def_id, const_substs.subst(tcx, substs)),
1193 #[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1194 pub struct TraitPredicate<'tcx> {
1195 pub trait_ref: TraitRef<'tcx>
1197 pub type PolyTraitPredicate<'tcx> = ty::Binder<TraitPredicate<'tcx>>;
1199 impl<'tcx> TraitPredicate<'tcx> {
1200 pub fn def_id(&self) -> DefId {
1201 self.trait_ref.def_id
1204 pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
1205 self.trait_ref.input_types()
1208 pub fn self_ty(&self) -> Ty<'tcx> {
1209 self.trait_ref.self_ty()
1213 impl<'tcx> PolyTraitPredicate<'tcx> {
1214 pub fn def_id(&self) -> DefId {
1215 // ok to skip binder since trait def-id does not care about regions
1216 self.skip_binder().def_id()
1220 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
1221 pub struct OutlivesPredicate<A,B>(pub A, pub B); // `A : B`
1222 pub type PolyOutlivesPredicate<A,B> = ty::Binder<OutlivesPredicate<A,B>>;
1223 pub type RegionOutlivesPredicate<'tcx> = OutlivesPredicate<ty::Region<'tcx>,
1225 pub type TypeOutlivesPredicate<'tcx> = OutlivesPredicate<Ty<'tcx>,
1227 pub type PolyRegionOutlivesPredicate<'tcx> = ty::Binder<RegionOutlivesPredicate<'tcx>>;
1228 pub type PolyTypeOutlivesPredicate<'tcx> = ty::Binder<TypeOutlivesPredicate<'tcx>>;
1230 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
1231 pub struct SubtypePredicate<'tcx> {
1232 pub a_is_expected: bool,
1236 pub type PolySubtypePredicate<'tcx> = ty::Binder<SubtypePredicate<'tcx>>;
1238 /// This kind of predicate has no *direct* correspondent in the
1239 /// syntax, but it roughly corresponds to the syntactic forms:
1241 /// 1. `T : TraitRef<..., Item=Type>`
1242 /// 2. `<T as TraitRef<...>>::Item == Type` (NYI)
1244 /// In particular, form #1 is "desugared" to the combination of a
1245 /// normal trait predicate (`T : TraitRef<...>`) and one of these
1246 /// predicates. Form #2 is a broader form in that it also permits
1247 /// equality between arbitrary types. Processing an instance of
1248 /// Form #2 eventually yields one of these `ProjectionPredicate`
1249 /// instances to normalize the LHS.
1250 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1251 pub struct ProjectionPredicate<'tcx> {
1252 pub projection_ty: ProjectionTy<'tcx>,
1256 pub type PolyProjectionPredicate<'tcx> = Binder<ProjectionPredicate<'tcx>>;
1258 impl<'tcx> PolyProjectionPredicate<'tcx> {
1259 /// Returns the def-id of the associated item being projected.
1260 pub fn item_def_id(&self) -> DefId {
1261 self.skip_binder().projection_ty.item_def_id
1264 pub fn to_poly_trait_ref(&self, tcx: TyCtxt) -> PolyTraitRef<'tcx> {
1265 // Note: unlike with TraitRef::to_poly_trait_ref(),
1266 // self.0.trait_ref is permitted to have escaping regions.
1267 // This is because here `self` has a `Binder` and so does our
1268 // return value, so we are preserving the number of binding
1270 self.map_bound(|predicate| predicate.projection_ty.trait_ref(tcx))
1273 pub fn ty(&self) -> Binder<Ty<'tcx>> {
1274 self.map_bound(|predicate| predicate.ty)
1277 /// The DefId of the TraitItem for the associated type.
1279 /// Note that this is not the DefId of the TraitRef containing this
1280 /// associated type, which is in tcx.associated_item(projection_def_id()).container.
1281 pub fn projection_def_id(&self) -> DefId {
1282 // ok to skip binder since trait def-id does not care about regions
1283 self.skip_binder().projection_ty.item_def_id
1287 pub trait ToPolyTraitRef<'tcx> {
1288 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx>;
1291 impl<'tcx> ToPolyTraitRef<'tcx> for TraitRef<'tcx> {
1292 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1293 ty::Binder::dummy(self.clone())
1297 impl<'tcx> ToPolyTraitRef<'tcx> for PolyTraitPredicate<'tcx> {
1298 fn to_poly_trait_ref(&self) -> PolyTraitRef<'tcx> {
1299 self.map_bound_ref(|trait_pred| trait_pred.trait_ref)
1303 pub trait ToPredicate<'tcx> {
1304 fn to_predicate(&self) -> Predicate<'tcx>;
1307 impl<'tcx> ToPredicate<'tcx> for TraitRef<'tcx> {
1308 fn to_predicate(&self) -> Predicate<'tcx> {
1309 ty::Predicate::Trait(ty::Binder::dummy(ty::TraitPredicate {
1310 trait_ref: self.clone()
1315 impl<'tcx> ToPredicate<'tcx> for PolyTraitRef<'tcx> {
1316 fn to_predicate(&self) -> Predicate<'tcx> {
1317 ty::Predicate::Trait(self.to_poly_trait_predicate())
1321 impl<'tcx> ToPredicate<'tcx> for PolyRegionOutlivesPredicate<'tcx> {
1322 fn to_predicate(&self) -> Predicate<'tcx> {
1323 Predicate::RegionOutlives(self.clone())
1327 impl<'tcx> ToPredicate<'tcx> for PolyTypeOutlivesPredicate<'tcx> {
1328 fn to_predicate(&self) -> Predicate<'tcx> {
1329 Predicate::TypeOutlives(self.clone())
1333 impl<'tcx> ToPredicate<'tcx> for PolyProjectionPredicate<'tcx> {
1334 fn to_predicate(&self) -> Predicate<'tcx> {
1335 Predicate::Projection(self.clone())
1339 impl<'tcx> Predicate<'tcx> {
1340 /// Iterates over the types in this predicate. Note that in all
1341 /// cases this is skipping over a binder, so late-bound regions
1342 /// with depth 0 are bound by the predicate.
1343 pub fn walk_tys(&self) -> IntoIter<Ty<'tcx>> {
1344 let vec: Vec<_> = match *self {
1345 ty::Predicate::Trait(ref data) => {
1346 data.skip_binder().input_types().collect()
1348 ty::Predicate::Subtype(binder) => {
1349 let SubtypePredicate { a, b, a_is_expected: _ } = binder.skip_binder();
1352 ty::Predicate::TypeOutlives(binder) => {
1353 vec![binder.skip_binder().0]
1355 ty::Predicate::RegionOutlives(..) => {
1358 ty::Predicate::Projection(ref data) => {
1359 let inner = data.skip_binder();
1360 inner.projection_ty.substs.types().chain(Some(inner.ty)).collect()
1362 ty::Predicate::WellFormed(data) => {
1365 ty::Predicate::ObjectSafe(_trait_def_id) => {
1368 ty::Predicate::ClosureKind(_closure_def_id, closure_substs, _kind) => {
1369 closure_substs.substs.types().collect()
1371 ty::Predicate::ConstEvaluatable(_, substs) => {
1372 substs.types().collect()
1376 // The only reason to collect into a vector here is that I was
1377 // too lazy to make the full (somewhat complicated) iterator
1378 // type that would be needed here. But I wanted this fn to
1379 // return an iterator conceptually, rather than a `Vec`, so as
1380 // to be closer to `Ty::walk`.
1384 pub fn to_opt_poly_trait_ref(&self) -> Option<PolyTraitRef<'tcx>> {
1386 Predicate::Trait(ref t) => {
1387 Some(t.to_poly_trait_ref())
1389 Predicate::Projection(..) |
1390 Predicate::Subtype(..) |
1391 Predicate::RegionOutlives(..) |
1392 Predicate::WellFormed(..) |
1393 Predicate::ObjectSafe(..) |
1394 Predicate::ClosureKind(..) |
1395 Predicate::TypeOutlives(..) |
1396 Predicate::ConstEvaluatable(..) => {
1402 pub fn to_opt_type_outlives(&self) -> Option<PolyTypeOutlivesPredicate<'tcx>> {
1404 Predicate::TypeOutlives(data) => {
1407 Predicate::Trait(..) |
1408 Predicate::Projection(..) |
1409 Predicate::Subtype(..) |
1410 Predicate::RegionOutlives(..) |
1411 Predicate::WellFormed(..) |
1412 Predicate::ObjectSafe(..) |
1413 Predicate::ClosureKind(..) |
1414 Predicate::ConstEvaluatable(..) => {
1421 /// Represents the bounds declared on a particular set of type
1422 /// parameters. Should eventually be generalized into a flag list of
1423 /// where clauses. You can obtain a `InstantiatedPredicates` list from a
1424 /// `GenericPredicates` by using the `instantiate` method. Note that this method
1425 /// reflects an important semantic invariant of `InstantiatedPredicates`: while
1426 /// the `GenericPredicates` are expressed in terms of the bound type
1427 /// parameters of the impl/trait/whatever, an `InstantiatedPredicates` instance
1428 /// represented a set of bounds for some particular instantiation,
1429 /// meaning that the generic parameters have been substituted with
1434 /// struct Foo<T,U:Bar<T>> { ... }
1436 /// Here, the `GenericPredicates` for `Foo` would contain a list of bounds like
1437 /// `[[], [U:Bar<T>]]`. Now if there were some particular reference
1438 /// like `Foo<isize,usize>`, then the `InstantiatedPredicates` would be `[[],
1439 /// [usize:Bar<isize>]]`.
1441 pub struct InstantiatedPredicates<'tcx> {
1442 pub predicates: Vec<Predicate<'tcx>>,
1445 impl<'tcx> InstantiatedPredicates<'tcx> {
1446 pub fn empty() -> InstantiatedPredicates<'tcx> {
1447 InstantiatedPredicates { predicates: vec![] }
1450 pub fn is_empty(&self) -> bool {
1451 self.predicates.is_empty()
1455 /// "Universes" are used during type- and trait-checking in the
1456 /// presence of `for<..>` binders to control what sets of names are
1457 /// visible. Universes are arranged into a tree: the root universe
1458 /// contains names that are always visible. But when you enter into
1459 /// some subuniverse, then it may add names that are only visible
1460 /// within that subtree (but it can still name the names of its
1461 /// ancestor universes).
1463 /// To make this more concrete, consider this program:
1467 /// fn bar<T>(x: T) {
1468 /// let y: for<'a> fn(&'a u8, Foo) = ...;
1472 /// The struct name `Foo` is in the root universe U0. But the type
1473 /// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
1474 /// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
1475 /// `bar`, we cannot name `T`. Then, within the type of `y`, the
1476 /// region `'a` is in a subuniverse U2 of U1, because we can name it
1477 /// inside the fn type but not outside.
1479 /// Universes are related to **skolemization** -- which is a way of
1480 /// doing type- and trait-checking around these "forall" binders (also
1481 /// called **universal quantification**). The idea is that when, in
1482 /// the body of `bar`, we refer to `T` as a type, we aren't referring
1483 /// to any type in particular, but rather a kind of "fresh" type that
1484 /// is distinct from all other types we have actually declared. This
1485 /// is called a **skolemized** type, and we use universes to talk
1486 /// about this. In other words, a type name in universe 0 always
1487 /// corresponds to some "ground" type that the user declared, but a
1488 /// type name in a non-zero universe is a skolemized type -- an
1489 /// idealized representative of "types in general" that we use for
1490 /// checking generic functions.
1491 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1492 pub struct UniverseIndex(u32);
1494 impl UniverseIndex {
1495 /// The root universe, where things that the user defined are
1497 pub const ROOT: Self = UniverseIndex(0);
1499 /// The "max universe" -- this isn't really a valid universe, but
1500 /// it's useful sometimes as a "starting value" when you are
1501 /// taking the minimum of a (non-empty!) set of universes.
1502 pub const MAX: Self = UniverseIndex(::std::u32::MAX);
1504 /// Creates a universe index from the given integer. Not to be
1505 /// used lightly lest you pick a bad value. But sometimes we
1506 /// convert universe indices into integers and back for various
1508 pub fn from_u32(index: u32) -> Self {
1509 UniverseIndex(index)
1512 /// A "subuniverse" corresponds to being inside a `forall` quantifier.
1513 /// So, for example, suppose we have this type in universe `U`:
1516 /// for<'a> fn(&'a u32)
1519 /// Once we "enter" into this `for<'a>` quantifier, we are in a
1520 /// subuniverse of `U` -- in this new universe, we can name the
1521 /// region `'a`, but that region was not nameable from `U` because
1522 /// it was not in scope there.
1523 pub fn subuniverse(self) -> UniverseIndex {
1524 UniverseIndex(self.0.checked_add(1).unwrap())
1527 /// True if the names in this universe are a subset of the names in `other`.
1528 pub fn is_subset_of(self, other: UniverseIndex) -> bool {
1532 pub fn as_u32(&self) -> u32 {
1536 pub fn as_usize(&self) -> usize {
1541 impl fmt::Debug for UniverseIndex {
1542 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
1543 write!(fmt, "U{}", self.as_u32())
1547 impl From<u32> for UniverseIndex {
1548 fn from(index: u32) -> Self {
1549 UniverseIndex(index)
1553 /// When type checking, we use the `ParamEnv` to track
1554 /// details about the set of where-clauses that are in scope at this
1555 /// particular point.
1556 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1557 pub struct ParamEnv<'tcx> {
1558 /// Obligations that the caller must satisfy. This is basically
1559 /// the set of bounds on the in-scope type parameters, translated
1560 /// into Obligations, and elaborated and normalized.
1561 pub caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1563 /// Typically, this is `Reveal::UserFacing`, but during codegen we
1564 /// want `Reveal::All` -- note that this is always paired with an
1565 /// empty environment. To get that, use `ParamEnv::reveal()`.
1566 pub reveal: traits::Reveal,
1569 impl<'tcx> ParamEnv<'tcx> {
1570 /// Construct a trait environment suitable for contexts where
1571 /// there are no where clauses in scope. Hidden types (like `impl
1572 /// Trait`) are left hidden, so this is suitable for ordinary
1574 pub fn empty() -> Self {
1575 Self::new(List::empty(), Reveal::UserFacing)
1578 /// Construct a trait environment with no where clauses in scope
1579 /// where the values of all `impl Trait` and other hidden types
1580 /// are revealed. This is suitable for monomorphized, post-typeck
1581 /// environments like codegen or doing optimizations.
1583 /// NB. If you want to have predicates in scope, use `ParamEnv::new`,
1584 /// or invoke `param_env.with_reveal_all()`.
1585 pub fn reveal_all() -> Self {
1586 Self::new(List::empty(), Reveal::All)
1589 /// Construct a trait environment with the given set of predicates.
1590 pub fn new(caller_bounds: &'tcx List<ty::Predicate<'tcx>>,
1593 ty::ParamEnv { caller_bounds, reveal }
1596 /// Returns a new parameter environment with the same clauses, but
1597 /// which "reveals" the true results of projections in all cases
1598 /// (even for associated types that are specializable). This is
1599 /// the desired behavior during codegen and certain other special
1600 /// contexts; normally though we want to use `Reveal::UserFacing`,
1601 /// which is the default.
1602 pub fn with_reveal_all(self) -> Self {
1603 ty::ParamEnv { reveal: Reveal::All, ..self }
1606 /// Returns this same environment but with no caller bounds.
1607 pub fn without_caller_bounds(self) -> Self {
1608 ty::ParamEnv { caller_bounds: List::empty(), ..self }
1611 /// Creates a suitable environment in which to perform trait
1612 /// queries on the given value. When type-checking, this is simply
1613 /// the pair of the environment plus value. But when reveal is set to
1614 /// All, then if `value` does not reference any type parameters, we will
1615 /// pair it with the empty environment. This improves caching and is generally
1618 /// NB: We preserve the environment when type-checking because it
1619 /// is possible for the user to have wacky where-clauses like
1620 /// `where Box<u32>: Copy`, which are clearly never
1621 /// satisfiable. We generally want to behave as if they were true,
1622 /// although the surrounding function is never reachable.
1623 pub fn and<T: TypeFoldable<'tcx>>(self, value: T) -> ParamEnvAnd<'tcx, T> {
1625 Reveal::UserFacing => {
1634 || value.needs_infer()
1635 || value.has_param_types()
1636 || value.has_self_ty()
1644 param_env: self.without_caller_bounds(),
1653 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
1654 pub struct ParamEnvAnd<'tcx, T> {
1655 pub param_env: ParamEnv<'tcx>,
1659 impl<'tcx, T> ParamEnvAnd<'tcx, T> {
1660 pub fn into_parts(self) -> (ParamEnv<'tcx>, T) {
1661 (self.param_env, self.value)
1665 impl<'a, 'gcx, T> HashStable<StableHashingContext<'a>> for ParamEnvAnd<'gcx, T>
1666 where T: HashStable<StableHashingContext<'a>>
1668 fn hash_stable<W: StableHasherResult>(&self,
1669 hcx: &mut StableHashingContext<'a>,
1670 hasher: &mut StableHasher<W>) {
1676 param_env.hash_stable(hcx, hasher);
1677 value.hash_stable(hcx, hasher);
1681 #[derive(Copy, Clone, Debug)]
1682 pub struct Destructor {
1683 /// The def-id of the destructor method
1688 pub struct AdtFlags: u32 {
1689 const NO_ADT_FLAGS = 0;
1690 const IS_ENUM = 1 << 0;
1691 const IS_PHANTOM_DATA = 1 << 1;
1692 const IS_FUNDAMENTAL = 1 << 2;
1693 const IS_UNION = 1 << 3;
1694 const IS_BOX = 1 << 4;
1695 /// Indicates whether the variant list of this ADT is `#[non_exhaustive]`.
1696 /// (i.e., this flag is never set unless this ADT is an enum).
1697 const IS_VARIANT_LIST_NON_EXHAUSTIVE = 1 << 5;
1702 pub struct VariantFlags: u32 {
1703 const NO_VARIANT_FLAGS = 0;
1704 /// Indicates whether the field list of this variant is `#[non_exhaustive]`.
1705 const IS_FIELD_LIST_NON_EXHAUSTIVE = 1 << 0;
1710 pub struct VariantDef {
1711 /// The variant's DefId. If this is a tuple-like struct,
1712 /// this is the DefId of the struct's ctor.
1714 pub name: Name, // struct's name if this is a struct
1715 pub discr: VariantDiscr,
1716 pub fields: Vec<FieldDef>,
1717 pub ctor_kind: CtorKind,
1718 flags: VariantFlags,
1721 impl<'a, 'gcx, 'tcx> VariantDef {
1722 /// Create a new `VariantDef`.
1724 /// - `did` is the DefId used for the variant - for tuple-structs, it is the constructor DefId,
1725 /// and for everything else, it is the variant DefId.
1726 /// - `attribute_def_id` is the DefId that has the variant's attributes.
1727 pub fn new(tcx: TyCtxt<'a, 'gcx, 'tcx>,
1730 discr: VariantDiscr,
1731 fields: Vec<FieldDef>,
1733 ctor_kind: CtorKind)
1736 debug!("VariantDef::new({:?}, {:?}, {:?}, {:?}, {:?}, {:?})", did, name, discr, fields,
1737 adt_kind, ctor_kind);
1738 let mut flags = VariantFlags::NO_VARIANT_FLAGS;
1739 if adt_kind == AdtKind::Struct && tcx.has_attr(did, "non_exhaustive") {
1740 debug!("found non-exhaustive field list for {:?}", did);
1741 flags = flags | VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE;
1754 pub fn is_field_list_non_exhaustive(&self) -> bool {
1755 self.flags.intersects(VariantFlags::IS_FIELD_LIST_NON_EXHAUSTIVE)
1759 impl_stable_hash_for!(struct VariantDef {
1768 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1769 pub enum VariantDiscr {
1770 /// Explicit value for this variant, i.e. `X = 123`.
1771 /// The `DefId` corresponds to the embedded constant.
1774 /// The previous variant's discriminant plus one.
1775 /// For efficiency reasons, the distance from the
1776 /// last `Explicit` discriminant is being stored,
1777 /// or `0` for the first variant, if it has none.
1782 pub struct FieldDef {
1785 pub vis: Visibility,
1788 /// The definition of an abstract data type - a struct or enum.
1790 /// These are all interned (by intern_adt_def) into the adt_defs
1794 pub variants: Vec<VariantDef>,
1796 pub repr: ReprOptions,
1799 impl PartialOrd for AdtDef {
1800 fn partial_cmp(&self, other: &AdtDef) -> Option<Ordering> {
1801 Some(self.cmp(&other))
1805 /// There should be only one AdtDef for each `did`, therefore
1806 /// it is fine to implement `Ord` only based on `did`.
1807 impl Ord for AdtDef {
1808 fn cmp(&self, other: &AdtDef) -> Ordering {
1809 self.did.cmp(&other.did)
1813 impl PartialEq for AdtDef {
1814 // AdtDef are always interned and this is part of TyS equality
1816 fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
1819 impl Eq for AdtDef {}
1821 impl Hash for AdtDef {
1823 fn hash<H: Hasher>(&self, s: &mut H) {
1824 (self as *const AdtDef).hash(s)
1828 impl<'tcx> serialize::UseSpecializedEncodable for &'tcx AdtDef {
1829 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1834 impl<'tcx> serialize::UseSpecializedDecodable for &'tcx AdtDef {}
1837 impl<'a> HashStable<StableHashingContext<'a>> for AdtDef {
1838 fn hash_stable<W: StableHasherResult>(&self,
1839 hcx: &mut StableHashingContext<'a>,
1840 hasher: &mut StableHasher<W>) {
1842 static CACHE: RefCell<FxHashMap<usize, Fingerprint>> =
1843 RefCell::new(FxHashMap());
1846 let hash: Fingerprint = CACHE.with(|cache| {
1847 let addr = self as *const AdtDef as usize;
1848 *cache.borrow_mut().entry(addr).or_insert_with(|| {
1856 let mut hasher = StableHasher::new();
1857 did.hash_stable(hcx, &mut hasher);
1858 variants.hash_stable(hcx, &mut hasher);
1859 flags.hash_stable(hcx, &mut hasher);
1860 repr.hash_stable(hcx, &mut hasher);
1866 hash.hash_stable(hcx, hasher);
1870 #[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
1871 pub enum AdtKind { Struct, Union, Enum }
1873 impl Into<DataTypeKind> for AdtKind {
1874 fn into(self) -> DataTypeKind {
1876 AdtKind::Struct => DataTypeKind::Struct,
1877 AdtKind::Union => DataTypeKind::Union,
1878 AdtKind::Enum => DataTypeKind::Enum,
1884 #[derive(RustcEncodable, RustcDecodable, Default)]
1885 pub struct ReprFlags: u8 {
1886 const IS_C = 1 << 0;
1887 const IS_SIMD = 1 << 1;
1888 const IS_TRANSPARENT = 1 << 2;
1889 // Internal only for now. If true, don't reorder fields.
1890 const IS_LINEAR = 1 << 3;
1892 // Any of these flags being set prevent field reordering optimisation.
1893 const IS_UNOPTIMISABLE = ReprFlags::IS_C.bits |
1894 ReprFlags::IS_SIMD.bits |
1895 ReprFlags::IS_LINEAR.bits;
1899 impl_stable_hash_for!(struct ReprFlags {
1905 /// Represents the repr options provided by the user,
1906 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Default)]
1907 pub struct ReprOptions {
1908 pub int: Option<attr::IntType>,
1911 pub flags: ReprFlags,
1914 impl_stable_hash_for!(struct ReprOptions {
1922 pub fn new(tcx: TyCtxt, did: DefId) -> ReprOptions {
1923 let mut flags = ReprFlags::empty();
1924 let mut size = None;
1925 let mut max_align = 0;
1926 let mut min_pack = 0;
1927 for attr in tcx.get_attrs(did).iter() {
1928 for r in attr::find_repr_attrs(tcx.sess.diagnostic(), attr) {
1929 flags.insert(match r {
1930 attr::ReprC => ReprFlags::IS_C,
1931 attr::ReprPacked(pack) => {
1932 min_pack = if min_pack > 0 {
1933 cmp::min(pack, min_pack)
1939 attr::ReprTransparent => ReprFlags::IS_TRANSPARENT,
1940 attr::ReprSimd => ReprFlags::IS_SIMD,
1941 attr::ReprInt(i) => {
1945 attr::ReprAlign(align) => {
1946 max_align = cmp::max(align, max_align);
1953 // This is here instead of layout because the choice must make it into metadata.
1954 if !tcx.consider_optimizing(|| format!("Reorder fields of {:?}", tcx.item_path_str(did))) {
1955 flags.insert(ReprFlags::IS_LINEAR);
1957 ReprOptions { int: size, align: max_align, pack: min_pack, flags: flags }
1961 pub fn simd(&self) -> bool { self.flags.contains(ReprFlags::IS_SIMD) }
1963 pub fn c(&self) -> bool { self.flags.contains(ReprFlags::IS_C) }
1965 pub fn packed(&self) -> bool { self.pack > 0 }
1967 pub fn transparent(&self) -> bool { self.flags.contains(ReprFlags::IS_TRANSPARENT) }
1969 pub fn linear(&self) -> bool { self.flags.contains(ReprFlags::IS_LINEAR) }
1971 pub fn discr_type(&self) -> attr::IntType {
1972 self.int.unwrap_or(attr::SignedInt(ast::IntTy::Isize))
1975 /// Returns true if this `#[repr()]` should inhabit "smart enum
1976 /// layout" optimizations, such as representing `Foo<&T>` as a
1978 pub fn inhibit_enum_layout_opt(&self) -> bool {
1979 self.c() || self.int.is_some()
1982 /// Returns true if this `#[repr()]` should inhibit struct field reordering
1983 /// optimizations, such as with repr(C) or repr(packed(1)).
1984 pub fn inhibit_struct_field_reordering_opt(&self) -> bool {
1985 !(self.flags & ReprFlags::IS_UNOPTIMISABLE).is_empty() || (self.pack == 1)
1989 impl<'a, 'gcx, 'tcx> AdtDef {
1993 variants: Vec<VariantDef>,
1994 repr: ReprOptions) -> Self {
1995 debug!("AdtDef::new({:?}, {:?}, {:?}, {:?})", did, kind, variants, repr);
1996 let mut flags = AdtFlags::NO_ADT_FLAGS;
1997 let attrs = tcx.get_attrs(did);
1998 if attr::contains_name(&attrs, "fundamental") {
1999 flags = flags | AdtFlags::IS_FUNDAMENTAL;
2001 if Some(did) == tcx.lang_items().phantom_data() {
2002 flags = flags | AdtFlags::IS_PHANTOM_DATA;
2004 if Some(did) == tcx.lang_items().owned_box() {
2005 flags = flags | AdtFlags::IS_BOX;
2007 if kind == AdtKind::Enum && tcx.has_attr(did, "non_exhaustive") {
2008 debug!("found non-exhaustive variant list for {:?}", did);
2009 flags = flags | AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE;
2012 AdtKind::Enum => flags = flags | AdtFlags::IS_ENUM,
2013 AdtKind::Union => flags = flags | AdtFlags::IS_UNION,
2014 AdtKind::Struct => {}
2025 pub fn is_struct(&self) -> bool {
2026 !self.is_union() && !self.is_enum()
2030 pub fn is_union(&self) -> bool {
2031 self.flags.intersects(AdtFlags::IS_UNION)
2035 pub fn is_enum(&self) -> bool {
2036 self.flags.intersects(AdtFlags::IS_ENUM)
2040 pub fn is_variant_list_non_exhaustive(&self) -> bool {
2041 self.flags.intersects(AdtFlags::IS_VARIANT_LIST_NON_EXHAUSTIVE)
2044 /// Returns the kind of the ADT - Struct or Enum.
2046 pub fn adt_kind(&self) -> AdtKind {
2049 } else if self.is_union() {
2056 pub fn descr(&self) -> &'static str {
2057 match self.adt_kind() {
2058 AdtKind::Struct => "struct",
2059 AdtKind::Union => "union",
2060 AdtKind::Enum => "enum",
2064 pub fn variant_descr(&self) -> &'static str {
2065 match self.adt_kind() {
2066 AdtKind::Struct => "struct",
2067 AdtKind::Union => "union",
2068 AdtKind::Enum => "variant",
2072 /// Returns whether this type is #[fundamental] for the purposes
2073 /// of coherence checking.
2075 pub fn is_fundamental(&self) -> bool {
2076 self.flags.intersects(AdtFlags::IS_FUNDAMENTAL)
2079 /// Returns true if this is PhantomData<T>.
2081 pub fn is_phantom_data(&self) -> bool {
2082 self.flags.intersects(AdtFlags::IS_PHANTOM_DATA)
2085 /// Returns true if this is Box<T>.
2087 pub fn is_box(&self) -> bool {
2088 self.flags.intersects(AdtFlags::IS_BOX)
2091 /// Returns whether this type has a destructor.
2092 pub fn has_dtor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> bool {
2093 self.destructor(tcx).is_some()
2096 /// Asserts this is a struct or union and returns its unique variant.
2097 pub fn non_enum_variant(&self) -> &VariantDef {
2098 assert!(self.is_struct() || self.is_union());
2103 pub fn predicates(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> GenericPredicates<'gcx> {
2104 tcx.predicates_of(self.did)
2107 /// Returns an iterator over all fields contained
2110 pub fn all_fields<'s>(&'s self) -> impl Iterator<Item = &'s FieldDef> {
2111 self.variants.iter().flat_map(|v| v.fields.iter())
2114 pub fn is_payloadfree(&self) -> bool {
2115 !self.variants.is_empty() &&
2116 self.variants.iter().all(|v| v.fields.is_empty())
2119 pub fn variant_with_id(&self, vid: DefId) -> &VariantDef {
2122 .find(|v| v.did == vid)
2123 .expect("variant_with_id: unknown variant")
2126 pub fn variant_index_with_id(&self, vid: DefId) -> usize {
2129 .position(|v| v.did == vid)
2130 .expect("variant_index_with_id: unknown variant")
2133 pub fn variant_of_def(&self, def: Def) -> &VariantDef {
2135 Def::Variant(vid) | Def::VariantCtor(vid, ..) => self.variant_with_id(vid),
2136 Def::Struct(..) | Def::StructCtor(..) | Def::Union(..) |
2137 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) |
2138 Def::SelfCtor(..) => self.non_enum_variant(),
2139 _ => bug!("unexpected def {:?} in variant_of_def", def)
2144 pub fn eval_explicit_discr(
2146 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2148 ) -> Option<Discr<'tcx>> {
2149 let param_env = ParamEnv::empty();
2150 let repr_type = self.repr.discr_type();
2151 let substs = Substs::identity_for_item(tcx.global_tcx(), expr_did);
2152 let instance = ty::Instance::new(expr_did, substs);
2153 let cid = GlobalId {
2157 match tcx.const_eval(param_env.and(cid)) {
2159 // FIXME: Find the right type and use it instead of `val.ty` here
2160 if let Some(b) = val.assert_bits(tcx.global_tcx(), param_env.and(val.ty)) {
2161 trace!("discriminants: {} ({:?})", b, repr_type);
2167 info!("invalid enum discriminant: {:#?}", val);
2168 ::mir::interpret::struct_error(
2169 tcx.at(tcx.def_span(expr_did)),
2170 "constant evaluation of enum discriminant resulted in non-integer",
2176 err.report_as_error(
2177 tcx.at(tcx.def_span(expr_did)),
2178 "could not evaluate enum discriminant",
2180 if !expr_did.is_local() {
2181 span_bug!(tcx.def_span(expr_did),
2182 "variant discriminant evaluation succeeded \
2183 in its crate but failed locally");
2191 pub fn discriminants(
2193 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2194 ) -> impl Iterator<Item=Discr<'tcx>> + Captures<'gcx> + 'a {
2195 let repr_type = self.repr.discr_type();
2196 let initial = repr_type.initial_discriminant(tcx.global_tcx());
2197 let mut prev_discr = None::<Discr<'tcx>>;
2198 self.variants.iter().map(move |v| {
2199 let mut discr = prev_discr.map_or(initial, |d| d.wrap_incr(tcx));
2200 if let VariantDiscr::Explicit(expr_did) = v.discr {
2201 if let Some(new_discr) = self.eval_explicit_discr(tcx, expr_did) {
2205 prev_discr = Some(discr);
2211 /// Compute the discriminant value used by a specific variant.
2212 /// Unlike `discriminants`, this is (amortized) constant-time,
2213 /// only doing at most one query for evaluating an explicit
2214 /// discriminant (the last one before the requested variant),
2215 /// assuming there are no constant-evaluation errors there.
2216 pub fn discriminant_for_variant(&self,
2217 tcx: TyCtxt<'a, 'gcx, 'tcx>,
2218 variant_index: usize)
2220 let (val, offset) = self.discriminant_def_for_variant(variant_index);
2221 let explicit_value = val
2222 .and_then(|expr_did| self.eval_explicit_discr(tcx, expr_did))
2223 .unwrap_or_else(|| self.repr.discr_type().initial_discriminant(tcx.global_tcx()));
2224 explicit_value.checked_add(tcx, offset as u128).0
2227 /// Yields a DefId for the discriminant and an offset to add to it
2228 /// Alternatively, if there is no explicit discriminant, returns the
2229 /// inferred discriminant directly
2230 pub fn discriminant_def_for_variant(
2232 variant_index: usize,
2233 ) -> (Option<DefId>, usize) {
2234 let mut explicit_index = variant_index;
2237 match self.variants[explicit_index].discr {
2238 ty::VariantDiscr::Relative(0) => {
2242 ty::VariantDiscr::Relative(distance) => {
2243 explicit_index -= distance;
2245 ty::VariantDiscr::Explicit(did) => {
2246 expr_did = Some(did);
2251 (expr_did, variant_index - explicit_index)
2254 pub fn destructor(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Option<Destructor> {
2255 tcx.adt_destructor(self.did)
2258 /// Returns a list of types such that `Self: Sized` if and only
2259 /// if that type is Sized, or `TyErr` if this type is recursive.
2261 /// Oddly enough, checking that the sized-constraint is Sized is
2262 /// actually more expressive than checking all members:
2263 /// the Sized trait is inductive, so an associated type that references
2264 /// Self would prevent its containing ADT from being Sized.
2266 /// Due to normalization being eager, this applies even if
2267 /// the associated type is behind a pointer, e.g. issue #31299.
2268 pub fn sized_constraint(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> &'tcx [Ty<'tcx>] {
2269 match tcx.try_adt_sized_constraint(DUMMY_SP, self.did) {
2272 debug!("adt_sized_constraint: {:?} is recursive", self);
2273 // This should be reported as an error by `check_representable`.
2275 // Consider the type as Sized in the meanwhile to avoid
2276 // further errors. Delay our `bug` diagnostic here to get
2277 // emitted later as well in case we accidentally otherwise don't
2280 tcx.intern_type_list(&[tcx.types.err])
2285 fn sized_constraint_for_ty(&self,
2286 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2289 let result = match ty.sty {
2290 Bool | Char | Int(..) | Uint(..) | Float(..) |
2291 RawPtr(..) | Ref(..) | FnDef(..) | FnPtr(_) |
2292 Array(..) | Closure(..) | Generator(..) | Never => {
2301 GeneratorWitness(..) => {
2302 // these are never sized - return the target type
2309 Some(ty) => self.sized_constraint_for_ty(tcx, ty)
2313 Adt(adt, substs) => {
2315 let adt_tys = adt.sized_constraint(tcx);
2316 debug!("sized_constraint_for_ty({:?}) intermediate = {:?}",
2319 .map(|ty| ty.subst(tcx, substs))
2320 .flat_map(|ty| self.sized_constraint_for_ty(tcx, ty))
2324 Projection(..) | Opaque(..) => {
2325 // must calculate explicitly.
2326 // FIXME: consider special-casing always-Sized projections
2331 // perf hack: if there is a `T: Sized` bound, then
2332 // we know that `T` is Sized and do not need to check
2335 let sized_trait = match tcx.lang_items().sized_trait() {
2337 _ => return vec![ty]
2339 let sized_predicate = Binder::dummy(TraitRef {
2340 def_id: sized_trait,
2341 substs: tcx.mk_substs_trait(ty, &[])
2343 let predicates = tcx.predicates_of(self.did).predicates;
2344 if predicates.into_iter().any(|p| p == sized_predicate) {
2352 bug!("unexpected type `{:?}` in sized_constraint_for_ty",
2356 debug!("sized_constraint_for_ty({:?}) = {:?}", ty, result);
2361 impl<'a, 'gcx, 'tcx> FieldDef {
2362 pub fn ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, subst: &Substs<'tcx>) -> Ty<'tcx> {
2363 tcx.type_of(self.did).subst(tcx, subst)
2367 /// Represents the various closure traits in the Rust language. This
2368 /// will determine the type of the environment (`self`, in the
2369 /// desuaring) argument that the closure expects.
2371 /// You can get the environment type of a closure using
2372 /// `tcx.closure_env_ty()`.
2373 #[derive(Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
2374 pub enum ClosureKind {
2375 // Warning: Ordering is significant here! The ordering is chosen
2376 // because the trait Fn is a subtrait of FnMut and so in turn, and
2377 // hence we order it so that Fn < FnMut < FnOnce.
2383 impl<'a, 'tcx> ClosureKind {
2384 // This is the initial value used when doing upvar inference.
2385 pub const LATTICE_BOTTOM: ClosureKind = ClosureKind::Fn;
2387 pub fn trait_did(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> DefId {
2389 ClosureKind::Fn => tcx.require_lang_item(FnTraitLangItem),
2390 ClosureKind::FnMut => {
2391 tcx.require_lang_item(FnMutTraitLangItem)
2393 ClosureKind::FnOnce => {
2394 tcx.require_lang_item(FnOnceTraitLangItem)
2399 /// True if this a type that impls this closure kind
2400 /// must also implement `other`.
2401 pub fn extends(self, other: ty::ClosureKind) -> bool {
2402 match (self, other) {
2403 (ClosureKind::Fn, ClosureKind::Fn) => true,
2404 (ClosureKind::Fn, ClosureKind::FnMut) => true,
2405 (ClosureKind::Fn, ClosureKind::FnOnce) => true,
2406 (ClosureKind::FnMut, ClosureKind::FnMut) => true,
2407 (ClosureKind::FnMut, ClosureKind::FnOnce) => true,
2408 (ClosureKind::FnOnce, ClosureKind::FnOnce) => true,
2413 /// Returns the representative scalar type for this closure kind.
2414 /// See `TyS::to_opt_closure_kind` for more details.
2415 pub fn to_ty(self, tcx: TyCtxt<'_, '_, 'tcx>) -> Ty<'tcx> {
2417 ty::ClosureKind::Fn => tcx.types.i8,
2418 ty::ClosureKind::FnMut => tcx.types.i16,
2419 ty::ClosureKind::FnOnce => tcx.types.i32,
2424 impl<'tcx> TyS<'tcx> {
2425 /// Iterator that walks `self` and any types reachable from
2426 /// `self`, in depth-first order. Note that just walks the types
2427 /// that appear in `self`, it does not descend into the fields of
2428 /// structs or variants. For example:
2431 /// isize => { isize }
2432 /// Foo<Bar<isize>> => { Foo<Bar<isize>>, Bar<isize>, isize }
2433 /// [isize] => { [isize], isize }
2435 pub fn walk(&'tcx self) -> TypeWalker<'tcx> {
2436 TypeWalker::new(self)
2439 /// Iterator that walks the immediate children of `self`. Hence
2440 /// `Foo<Bar<i32>, u32>` yields the sequence `[Bar<i32>, u32]`
2441 /// (but not `i32`, like `walk`).
2442 pub fn walk_shallow(&'tcx self) -> smallvec::IntoIter<walk::TypeWalkerArray<'tcx>> {
2443 walk::walk_shallow(self)
2446 /// Walks `ty` and any types appearing within `ty`, invoking the
2447 /// callback `f` on each type. If the callback returns false, then the
2448 /// children of the current type are ignored.
2450 /// Note: prefer `ty.walk()` where possible.
2451 pub fn maybe_walk<F>(&'tcx self, mut f: F)
2452 where F : FnMut(Ty<'tcx>) -> bool
2454 let mut walker = self.walk();
2455 while let Some(ty) = walker.next() {
2457 walker.skip_current_subtree();
2464 pub fn from_mutbl(m: hir::Mutability) -> BorrowKind {
2466 hir::MutMutable => MutBorrow,
2467 hir::MutImmutable => ImmBorrow,
2471 /// Returns a mutability `m` such that an `&m T` pointer could be used to obtain this borrow
2472 /// kind. Because borrow kinds are richer than mutabilities, we sometimes have to pick a
2473 /// mutability that is stronger than necessary so that it at least *would permit* the borrow in
2475 pub fn to_mutbl_lossy(self) -> hir::Mutability {
2477 MutBorrow => hir::MutMutable,
2478 ImmBorrow => hir::MutImmutable,
2480 // We have no type corresponding to a unique imm borrow, so
2481 // use `&mut`. It gives all the capabilities of an `&uniq`
2482 // and hence is a safe "over approximation".
2483 UniqueImmBorrow => hir::MutMutable,
2487 pub fn to_user_str(&self) -> &'static str {
2489 MutBorrow => "mutable",
2490 ImmBorrow => "immutable",
2491 UniqueImmBorrow => "uniquely immutable",
2496 #[derive(Debug, Clone)]
2497 pub enum Attributes<'gcx> {
2498 Owned(Lrc<[ast::Attribute]>),
2499 Borrowed(&'gcx [ast::Attribute])
2502 impl<'gcx> ::std::ops::Deref for Attributes<'gcx> {
2503 type Target = [ast::Attribute];
2505 fn deref(&self) -> &[ast::Attribute] {
2507 &Attributes::Owned(ref data) => &data,
2508 &Attributes::Borrowed(data) => data
2513 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2514 pub fn body_tables(self, body: hir::BodyId) -> &'gcx TypeckTables<'gcx> {
2515 self.typeck_tables_of(self.hir.body_owner_def_id(body))
2518 /// Returns an iterator of the def-ids for all body-owners in this
2519 /// crate. If you would prefer to iterate over the bodies
2520 /// themselves, you can do `self.hir.krate().body_ids.iter()`.
2523 ) -> impl Iterator<Item = DefId> + Captures<'tcx> + Captures<'gcx> + 'a {
2527 .map(move |&body_id| self.hir.body_owner_def_id(body_id))
2530 pub fn par_body_owners<F: Fn(DefId) + sync::Sync + sync::Send>(self, f: F) {
2531 par_iter(&self.hir.krate().body_ids).for_each(|&body_id| {
2532 f(self.hir.body_owner_def_id(body_id))
2536 pub fn expr_span(self, id: NodeId) -> Span {
2537 match self.hir.find(id) {
2538 Some(Node::Expr(e)) => {
2542 bug!("Node id {} is not an expr: {:?}", id, f);
2545 bug!("Node id {} is not present in the node map", id);
2550 pub fn provided_trait_methods(self, id: DefId) -> Vec<AssociatedItem> {
2551 self.associated_items(id)
2552 .filter(|item| item.kind == AssociatedKind::Method && item.defaultness.has_value())
2556 pub fn trait_relevant_for_never(self, did: DefId) -> bool {
2557 self.associated_items(did).any(|item| {
2558 item.relevant_for_never()
2562 pub fn opt_associated_item(self, def_id: DefId) -> Option<AssociatedItem> {
2563 let is_associated_item = if let Some(node_id) = self.hir.as_local_node_id(def_id) {
2564 match self.hir.get(node_id) {
2565 Node::TraitItem(_) | Node::ImplItem(_) => true,
2569 match self.describe_def(def_id).expect("no def for def-id") {
2570 Def::AssociatedConst(_) | Def::Method(_) | Def::AssociatedTy(_) => true,
2575 if is_associated_item {
2576 Some(self.associated_item(def_id))
2582 fn associated_item_from_trait_item_ref(self,
2583 parent_def_id: DefId,
2584 parent_vis: &hir::Visibility,
2585 trait_item_ref: &hir::TraitItemRef)
2587 let def_id = self.hir.local_def_id(trait_item_ref.id.node_id);
2588 let (kind, has_self) = match trait_item_ref.kind {
2589 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2590 hir::AssociatedItemKind::Method { has_self } => {
2591 (ty::AssociatedKind::Method, has_self)
2593 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2594 hir::AssociatedItemKind::Existential => bug!("only impls can have existentials"),
2598 ident: trait_item_ref.ident,
2600 // Visibility of trait items is inherited from their traits.
2601 vis: Visibility::from_hir(parent_vis, trait_item_ref.id.node_id, self),
2602 defaultness: trait_item_ref.defaultness,
2604 container: TraitContainer(parent_def_id),
2605 method_has_self_argument: has_self
2609 fn associated_item_from_impl_item_ref(self,
2610 parent_def_id: DefId,
2611 impl_item_ref: &hir::ImplItemRef)
2613 let def_id = self.hir.local_def_id(impl_item_ref.id.node_id);
2614 let (kind, has_self) = match impl_item_ref.kind {
2615 hir::AssociatedItemKind::Const => (ty::AssociatedKind::Const, false),
2616 hir::AssociatedItemKind::Method { has_self } => {
2617 (ty::AssociatedKind::Method, has_self)
2619 hir::AssociatedItemKind::Type => (ty::AssociatedKind::Type, false),
2620 hir::AssociatedItemKind::Existential => (ty::AssociatedKind::Existential, false),
2624 ident: impl_item_ref.ident,
2626 // Visibility of trait impl items doesn't matter.
2627 vis: ty::Visibility::from_hir(&impl_item_ref.vis, impl_item_ref.id.node_id, self),
2628 defaultness: impl_item_ref.defaultness,
2630 container: ImplContainer(parent_def_id),
2631 method_has_self_argument: has_self
2635 pub fn field_index(self, node_id: NodeId, tables: &TypeckTables) -> usize {
2636 let hir_id = self.hir.node_to_hir_id(node_id);
2637 tables.field_indices().get(hir_id).cloned().expect("no index for a field")
2640 pub fn find_field_index(self, ident: Ident, variant: &VariantDef) -> Option<usize> {
2641 variant.fields.iter().position(|field| {
2642 self.adjust_ident(ident, variant.did, DUMMY_NODE_ID).0 == field.ident.modern()
2646 pub fn associated_items(
2649 ) -> impl Iterator<Item = AssociatedItem> + 'a {
2650 let def_ids = self.associated_item_def_ids(def_id);
2651 Box::new((0..def_ids.len()).map(move |i| self.associated_item(def_ids[i])))
2652 as Box<dyn Iterator<Item = AssociatedItem> + 'a>
2655 /// Returns true if the impls are the same polarity and are implementing
2656 /// a trait which contains no items
2657 pub fn impls_are_allowed_to_overlap(self, def_id1: DefId, def_id2: DefId) -> bool {
2658 if !self.features().overlapping_marker_traits {
2661 let trait1_is_empty = self.impl_trait_ref(def_id1)
2662 .map_or(false, |trait_ref| {
2663 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2665 let trait2_is_empty = self.impl_trait_ref(def_id2)
2666 .map_or(false, |trait_ref| {
2667 self.associated_item_def_ids(trait_ref.def_id).is_empty()
2669 self.impl_polarity(def_id1) == self.impl_polarity(def_id2)
2674 // Returns `ty::VariantDef` if `def` refers to a struct,
2675 // or variant or their constructors, panics otherwise.
2676 pub fn expect_variant_def(self, def: Def) -> &'tcx VariantDef {
2678 Def::Variant(did) | Def::VariantCtor(did, ..) => {
2679 let enum_did = self.parent_def_id(did).unwrap();
2680 self.adt_def(enum_did).variant_with_id(did)
2682 Def::Struct(did) | Def::Union(did) => {
2683 self.adt_def(did).non_enum_variant()
2685 Def::StructCtor(ctor_did, ..) => {
2686 let did = self.parent_def_id(ctor_did).expect("struct ctor has no parent");
2687 self.adt_def(did).non_enum_variant()
2689 _ => bug!("expect_variant_def used with unexpected def {:?}", def)
2693 /// Given a `VariantDef`, returns the def-id of the `AdtDef` of which it is a part.
2694 pub fn adt_def_id_of_variant(self, variant_def: &'tcx VariantDef) -> DefId {
2695 let def_key = self.def_key(variant_def.did);
2696 match def_key.disambiguated_data.data {
2697 // for enum variants and tuple structs, the def-id of the ADT itself
2698 // is the *parent* of the variant
2699 DefPathData::EnumVariant(..) | DefPathData::StructCtor =>
2700 DefId { krate: variant_def.did.krate, index: def_key.parent.unwrap() },
2702 // otherwise, for structs and unions, they share a def-id
2703 _ => variant_def.did,
2707 pub fn item_name(self, id: DefId) -> InternedString {
2708 if id.index == CRATE_DEF_INDEX {
2709 self.original_crate_name(id.krate).as_interned_str()
2711 let def_key = self.def_key(id);
2712 // The name of a StructCtor is that of its struct parent.
2713 if let hir_map::DefPathData::StructCtor = def_key.disambiguated_data.data {
2714 self.item_name(DefId {
2716 index: def_key.parent.unwrap()
2719 def_key.disambiguated_data.data.get_opt_name().unwrap_or_else(|| {
2720 bug!("item_name: no name for {:?}", self.def_path(id));
2726 /// Return the possibly-auto-generated MIR of a (DefId, Subst) pair.
2727 pub fn instance_mir(self, instance: ty::InstanceDef<'gcx>)
2731 ty::InstanceDef::Item(did) => {
2732 self.optimized_mir(did)
2734 ty::InstanceDef::Intrinsic(..) |
2735 ty::InstanceDef::FnPtrShim(..) |
2736 ty::InstanceDef::Virtual(..) |
2737 ty::InstanceDef::ClosureOnceShim { .. } |
2738 ty::InstanceDef::DropGlue(..) |
2739 ty::InstanceDef::CloneShim(..) => {
2740 self.mir_shims(instance)
2745 /// Given the DefId of an item, returns its MIR, borrowed immutably.
2746 /// Returns None if there is no MIR for the DefId
2747 pub fn maybe_optimized_mir(self, did: DefId) -> Option<&'gcx Mir<'gcx>> {
2748 if self.is_mir_available(did) {
2749 Some(self.optimized_mir(did))
2755 /// Get the attributes of a definition.
2756 pub fn get_attrs(self, did: DefId) -> Attributes<'gcx> {
2757 if let Some(id) = self.hir.as_local_node_id(did) {
2758 Attributes::Borrowed(self.hir.attrs(id))
2760 Attributes::Owned(self.item_attrs(did))
2764 /// Determine whether an item is annotated with an attribute
2765 pub fn has_attr(self, did: DefId, attr: &str) -> bool {
2766 attr::contains_name(&self.get_attrs(did), attr)
2769 /// Returns true if this is an `auto trait`.
2770 pub fn trait_is_auto(self, trait_def_id: DefId) -> bool {
2771 self.trait_def(trait_def_id).has_auto_impl
2774 pub fn generator_layout(self, def_id: DefId) -> &'tcx GeneratorLayout<'tcx> {
2775 self.optimized_mir(def_id).generator_layout.as_ref().unwrap()
2778 /// Given the def_id of an impl, return the def_id of the trait it implements.
2779 /// If it implements no trait, return `None`.
2780 pub fn trait_id_of_impl(self, def_id: DefId) -> Option<DefId> {
2781 self.impl_trait_ref(def_id).map(|tr| tr.def_id)
2784 /// If the given def ID describes a method belonging to an impl, return the
2785 /// ID of the impl that the method belongs to. Otherwise, return `None`.
2786 pub fn impl_of_method(self, def_id: DefId) -> Option<DefId> {
2787 let item = if def_id.krate != LOCAL_CRATE {
2788 if let Some(Def::Method(_)) = self.describe_def(def_id) {
2789 Some(self.associated_item(def_id))
2794 self.opt_associated_item(def_id)
2797 item.and_then(|trait_item|
2798 match trait_item.container {
2799 TraitContainer(_) => None,
2800 ImplContainer(def_id) => Some(def_id),
2805 /// Looks up the span of `impl_did` if the impl is local; otherwise returns `Err`
2806 /// with the name of the crate containing the impl.
2807 pub fn span_of_impl(self, impl_did: DefId) -> Result<Span, Symbol> {
2808 if impl_did.is_local() {
2809 let node_id = self.hir.as_local_node_id(impl_did).unwrap();
2810 Ok(self.hir.span(node_id))
2812 Err(self.crate_name(impl_did.krate))
2816 // Hygienically compare a use-site name (`use_name`) for a field or an associated item with its
2817 // supposed definition name (`def_name`). The method also needs `DefId` of the supposed
2818 // definition's parent/scope to perform comparison.
2819 pub fn hygienic_eq(self, use_name: Ident, def_name: Ident, def_parent_def_id: DefId) -> bool {
2820 self.adjust_ident(use_name, def_parent_def_id, DUMMY_NODE_ID).0 == def_name.modern()
2823 pub fn adjust_ident(self, mut ident: Ident, scope: DefId, block: NodeId) -> (Ident, DefId) {
2824 ident = ident.modern();
2825 let target_expansion = match scope.krate {
2826 LOCAL_CRATE => self.hir.definitions().expansion_that_defined(scope.index),
2829 let scope = match ident.span.adjust(target_expansion) {
2830 Some(actual_expansion) =>
2831 self.hir.definitions().parent_module_of_macro_def(actual_expansion),
2832 None if block == DUMMY_NODE_ID => DefId::local(CRATE_DEF_INDEX), // Dummy DefId
2833 None => self.hir.get_module_parent(block),
2839 impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
2840 pub fn with_freevars<T, F>(self, fid: NodeId, f: F) -> T where
2841 F: FnOnce(&[hir::Freevar]) -> T,
2843 let def_id = self.hir.local_def_id(fid);
2844 match self.freevars(def_id) {
2851 fn associated_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
2854 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2855 let parent_id = tcx.hir.get_parent(id);
2856 let parent_def_id = tcx.hir.local_def_id(parent_id);
2857 let parent_item = tcx.hir.expect_item(parent_id);
2858 match parent_item.node {
2859 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2860 if let Some(impl_item_ref) = impl_item_refs.iter().find(|i| i.id.node_id == id) {
2861 let assoc_item = tcx.associated_item_from_impl_item_ref(parent_def_id,
2863 debug_assert_eq!(assoc_item.def_id, def_id);
2868 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2869 if let Some(trait_item_ref) = trait_item_refs.iter().find(|i| i.id.node_id == id) {
2870 let assoc_item = tcx.associated_item_from_trait_item_ref(parent_def_id,
2873 debug_assert_eq!(assoc_item.def_id, def_id);
2881 span_bug!(parent_item.span,
2882 "unexpected parent of trait or impl item or item not found: {:?}",
2886 /// Calculates the Sized-constraint.
2888 /// In fact, there are only a few options for the types in the constraint:
2889 /// - an obviously-unsized type
2890 /// - a type parameter or projection whose Sizedness can't be known
2891 /// - a tuple of type parameters or projections, if there are multiple
2893 /// - a Error, if a type contained itself. The representability
2894 /// check should catch this case.
2895 fn adt_sized_constraint<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2897 -> &'tcx [Ty<'tcx>] {
2898 let def = tcx.adt_def(def_id);
2900 let result = tcx.mk_type_list(def.variants.iter().flat_map(|v| {
2903 def.sized_constraint_for_ty(tcx, tcx.type_of(f.did))
2906 debug!("adt_sized_constraint: {:?} => {:?}", def, result);
2911 fn associated_item_def_ids<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2913 -> Lrc<Vec<DefId>> {
2914 let id = tcx.hir.as_local_node_id(def_id).unwrap();
2915 let item = tcx.hir.expect_item(id);
2916 let vec: Vec<_> = match item.node {
2917 hir::ItemKind::Trait(.., ref trait_item_refs) => {
2918 trait_item_refs.iter()
2919 .map(|trait_item_ref| trait_item_ref.id)
2920 .map(|id| tcx.hir.local_def_id(id.node_id))
2923 hir::ItemKind::Impl(.., ref impl_item_refs) => {
2924 impl_item_refs.iter()
2925 .map(|impl_item_ref| impl_item_ref.id)
2926 .map(|id| tcx.hir.local_def_id(id.node_id))
2929 hir::ItemKind::TraitAlias(..) => vec![],
2930 _ => span_bug!(item.span, "associated_item_def_ids: not impl or trait")
2935 fn def_span<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Span {
2936 tcx.hir.span_if_local(def_id).unwrap()
2939 /// If the given def ID describes an item belonging to a trait,
2940 /// return the ID of the trait that the trait item belongs to.
2941 /// Otherwise, return `None`.
2942 fn trait_of_item<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Option<DefId> {
2943 tcx.opt_associated_item(def_id)
2944 .and_then(|associated_item| {
2945 match associated_item.container {
2946 TraitContainer(def_id) => Some(def_id),
2947 ImplContainer(_) => None
2952 /// Yields the parent function's `DefId` if `def_id` is an `impl Trait` definition
2953 pub fn is_impl_trait_defn(tcx: TyCtxt, def_id: DefId) -> Option<DefId> {
2954 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2955 if let Node::Item(item) = tcx.hir.get(node_id) {
2956 if let hir::ItemKind::Existential(ref exist_ty) = item.node {
2957 return exist_ty.impl_trait_fn;
2964 /// See `ParamEnv` struct def'n for details.
2965 fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
2969 // The param_env of an impl Trait type is its defining function's param_env
2970 if let Some(parent) = is_impl_trait_defn(tcx, def_id) {
2971 return param_env(tcx, parent);
2973 // Compute the bounds on Self and the type parameters.
2975 let InstantiatedPredicates { predicates } =
2976 tcx.predicates_of(def_id).instantiate_identity(tcx);
2978 // Finally, we have to normalize the bounds in the environment, in
2979 // case they contain any associated type projections. This process
2980 // can yield errors if the put in illegal associated types, like
2981 // `<i32 as Foo>::Bar` where `i32` does not implement `Foo`. We
2982 // report these errors right here; this doesn't actually feel
2983 // right to me, because constructing the environment feels like a
2984 // kind of a "idempotent" action, but I'm not sure where would be
2985 // a better place. In practice, we construct environments for
2986 // every fn once during type checking, and we'll abort if there
2987 // are any errors at that point, so after type checking you can be
2988 // sure that this will succeed without errors anyway.
2990 let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
2991 traits::Reveal::UserFacing);
2993 let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
2994 tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
2996 let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
2997 traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
3000 fn crate_disambiguator<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3001 crate_num: CrateNum) -> CrateDisambiguator {
3002 assert_eq!(crate_num, LOCAL_CRATE);
3003 tcx.sess.local_crate_disambiguator()
3006 fn original_crate_name<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3007 crate_num: CrateNum) -> Symbol {
3008 assert_eq!(crate_num, LOCAL_CRATE);
3009 tcx.crate_name.clone()
3012 fn crate_hash<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3013 crate_num: CrateNum)
3015 assert_eq!(crate_num, LOCAL_CRATE);
3019 fn instance_def_size_estimate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
3020 instance_def: InstanceDef<'tcx>)
3022 match instance_def {
3023 InstanceDef::Item(..) |
3024 InstanceDef::DropGlue(..) => {
3025 let mir = tcx.instance_mir(instance_def);
3026 mir.basic_blocks().iter().map(|bb| bb.statements.len()).sum()
3028 // Estimate the size of other compiler-generated shims to be 1.
3033 pub fn provide(providers: &mut ty::query::Providers) {
3034 context::provide(providers);
3035 erase_regions::provide(providers);
3036 layout::provide(providers);
3037 util::provide(providers);
3038 *providers = ty::query::Providers {
3040 associated_item_def_ids,
3041 adt_sized_constraint,
3045 crate_disambiguator,
3046 original_crate_name,
3048 trait_impls_of: trait_def::trait_impls_of_provider,
3049 instance_def_size_estimate,
3054 /// A map for the local crate mapping each type to a vector of its
3055 /// inherent impls. This is not meant to be used outside of coherence;
3056 /// rather, you should request the vector for a specific type via
3057 /// `tcx.inherent_impls(def_id)` so as to minimize your dependencies
3058 /// (constructing this map requires touching the entire crate).
3059 #[derive(Clone, Debug)]
3060 pub struct CrateInherentImpls {
3061 pub inherent_impls: DefIdMap<Lrc<Vec<DefId>>>,
3064 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
3065 pub struct SymbolName {
3066 // FIXME: we don't rely on interning or equality here - better have
3067 // this be a `&'tcx str`.
3068 pub name: InternedString
3071 impl_stable_hash_for!(struct self::SymbolName {
3076 pub fn new(name: &str) -> SymbolName {
3078 name: Symbol::intern(name).as_interned_str()
3082 pub fn as_str(&self) -> LocalInternedString {
3087 impl fmt::Display for SymbolName {
3088 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
3089 fmt::Display::fmt(&self.name, fmt)
3093 impl fmt::Debug for SymbolName {
3094 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
3095 fmt::Display::fmt(&self.name, fmt)